How a solar-powered watermaker generates fresh water from seawater. When you’re on a boat out on the ocean, it feels a little like being on a spaceship. At least, it does to me. Your boat is a self-contained vessel. You must provide all your food and water before you sail.
A super solar-powered watermaker has been invented. You could generate all the fresh water you need. This solar-powered watermaker is cheap to make, and soon to buy. And, because it is completely passive, it is totally free. Not only that, the water is ultra pure because it is distilled instead of filtered. Also, it is highly efficient, eco-friendly and free to operate!
The Two Main Ways to Get Fresh Water
For water: you can catch rainwater, you can buy water before you leave, or you can make your own. Making your own water can be expensive. There are really only two ways to make fresh water: distillation and filtering.
Commercial Ships Use Waste Engine Heat for Distillation
Commercial ships use distillation. This means they boil the seawater to make steam. Then they condense it back to distilled water. This takes energy, but already run their engines. They use the extra heat from their engines. Therefore, it’s almost free.
Sailboats Rely on “Watermaker” Filters for Fresh Water
Sailboats don’t have waste heat because they don’t usually run their engines. As a result, so they use filtration. Sailboats use a filtering process called reverse osmosis (RO). However, this isn’t cheap. The filters cost money and they only work under high pressure, which uses a lot of energy. Boaters generally call these filters “Watermakers.”
Watermakers are Expensive
High end water systems can cost $6000. Even watermaker kits can cost $3000 and up. DIY systems are available, but you must have the tools, spend the time and assemble the parts. And, these DIY systems still cost thousands. Besides, all of these water making systems need monitoring and maintenance. In addition, all these water maker require lots of power.
Sailboats usually power their watermakers from Diesel engines, generators or from electric motors, which are powered by generators. All of these use fuel. And, fuel is costly. As a result, watermakers are expensive.
Solar Stills
A solar still purifies water with dissolved contaminates by using the heat of the Sun. The sun’s energy heats water to the point of evaporation. As the water evaporates, its vapor rises, and condensing into pure water again as it cools. A solar still is a type of solar-powered watermaker.
Distillation replicates the way nature makes rain. A solar still works on two scientific principles: evaporation and condensation. Distilled water is purified because the salts and minerals are left behind in a residue.
The problem is that solar stills aren’t very efficient. They use free solar energy to evaporate water. However, some of the energy is wasted as heat and is lost. This makes the process less efficient.
Recent attempts to improve this efficiency ended up making the process very costly.
Toward A More Efficient Watermaker
A team at MIT has just invented a new design for making fresh water. It’s completely passive, totally quiet and ultra efficient. That’s because this design is a multi layer solar still. It relies on the solid idea of a solar still. They call it a “thermally-localized multistage solar still” or TMSS.
OK. Stills have been know for ages. However, they weren’t productive. That’s because they were only one layer thick. There have been other attempts to improve the solar still, but they failed. That’s because they combined the two parts together. This made the device both costly to make and less efficient to use. Besides, they were not simple. In addition, they still wasted heat.
In a basic solar still, the sun heats the seawater. This boils the water into steam. The steam condenses into distilled water, which released that heat. However, this was a tiny amount of water and the wasted energy was lost to the environment.
Ultra solar-powered watermaker
How They Fixed the Solar Still
This new process fixes that. The team was able to harness the wasted heat by adding multiple layers. In their proof-of-concept model, the team stacked ten layers together. Each layer measured one square meter. Each layer produced a small amount of water as normal, but then recycled the heat to the next layer.
Adding up the water output, the unit produced an astonishing 1.5 gallons (5.78 liters) of fresh drinking water per hour, achieving an astonishing overall efficiency of 385 percent.
Efficiency Up to 700 or 800 Percent
The best part is still to come. There isn’t a limit on the size of the panels or the number of layers. Therefore, the team thinks that up to 700 or 800 percent efficiency may be possible with some changes.
Passive Solar Doesn’t Need Power
Previously, all water making systems required lots of power. Distillation on commercial ships required engine heat to generate steam. RO filtration on sailboats require high pressure. Belt-drives to engines or electric power, either 110 VAC or 12/24 VDC supply this power.
This system is completely passive and highly efficient. It doesn’t need the waste heat of commercial ship engines. And, it doesn’t even need high pressure for filters. In fact, it makes and reuses it’s own power from solar heat. This is revolutionary and this solar-powered watermaker will likely be available commercially very soon.
The sun provides all the heat to boil the seawater. The first layer captures that lost heat and reuses it. This layer boils more water, which then gets reused. This watermaker is ultra efficient because it has multiple layers. The first truly solar-powered watermaker.
High Quality Distilled Water
This model only measures one meter square and yet produces 1.5 gallons (5.78 liters) of fresh drinking water per hour. Distilled water is pure. When it was tested, this water exceeded the city standards. Besides, it’s free from the sun. In other words, this water is higher quality and cheaper than filtered.
This Watermaker is Eco Friendly
Desalination systems return the salt water to the sea as a salt brine, which harms marine life. This solar still system does not return the salt as a brine. The salt is returned to the sea passively through diffusion during the night. This means less damage to the environment. Besides, boaters care about the coral reefs.
Ordinary Materials and Paper Towels
The demo unit was built from materials such as paper towels. The towels form the wick and carry the water to the solar absorber. The absorber does the heating. Then the layer passes the heat to the next layer. This is how this new design improves on other systems.
Making Two Layers Meant Ordinary Materials
Previous attempts combined the absorber layer and the wick layer as one part. This meant these systems needed costly materials. By separating these functions into two parts, this team was able to find ordinary materials. In addition, this makes for easier repairs. Besides, it was simpler.
Could Be Used Anywhere
The real-world implications are amazing. This could easily reduce water issues in the developing world. For example, on a boat. In fact, it could be used anywhere electricity is scarce or expensive and seawater and sunlight are abundant.
Replacing Solar Panels
One ten-layer system could meet the water needs for one person. A family sized system might cost $100. Most sailboats have a solar panel this size already. Besides, the cost savings would replace the solar panel. In addition, this would be a smaller device.
Conclusions
In conclusion, I am excited about this! The solar still is a time-tested design that works by imitating nature. However, it has many limitations. This device takes all of those limitations and turns them into advantages. The device uses zero energy; it is completely passive solar. Besides, it works quietly and full-time. Also, the capacity is adequate and the water is pure.
One of the best features is that it’s made of ordinary parts, not expensive tech things which are hard-to-find when you need them. It doesn’t make a brine to hurt the coral reefs and it can be used anywhere, especially where electricity is expensive or difficult and where sunshine and seawater are abundant. Like a sailboat!
Randy
Sources:
https://dspace.mit.edu/handle/1721.1/123794